Safety means for chairs



Jan. 9, 1934- w, A. SENGPIEL 1,942,781

SAFETY MEANS FOR CHAIRS x Filed April 4, 1931 i wf #MAW .MW

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Patented `ian. 9, 1934 UNiTED STATES PATENT QFFIQ SAFETY MEANS FOR CHAIRS Application April 4, 1

s claims.

My invention relates to chairs of the type commonly known as typewriter7 chairs of the character in which the chair seat is pivotally supported upon a chair iron or other supporting means, but is applicable to chairs of other types wherein the seat has pivotal connection with the base or supporting structure of the chair. In such chairs the seat is held normally in position by means of one or more springs the tension of which is adapted to be varied by means of suitable adjusting means. If, while a chair of that character is in use, the means or device for adjusting the tension of the springs should break or otherwise become ineffective it might happen that the person sitting on the chair would fall or be thrown backward therefrom by reason of the unrestrained backward tilting of the chair seat and back associated therewith. It will be apparent that means to prevent such unrestrained backward tilting in such case would serve a most useful purpose or function.

It is the general object of this invention to provide a safety attachment or means supplemental to the main spring and the adjusting means therefor for yieldingly preventing unrestrained backward tilting of the chair seat in case of breakage of the tensioning and holding means for the main spring or springs.

Without attempting to set forth more fully the general objects oi my invention I shall now proceed with a detailed description thereof wherein other or additional objects will be set forth or else will be apparent therefrom.

In order that the invention may be readily understood and its practical advantages fully appreciated reference should be had to the accompanying drawing wherein I have illustrated one mechanical embodiment of the invention in a form which has been found to be highly satisfactory, but it should be understood that the invention may be embodied in other forms of construction than that shown and that changes in the details of construction may be made within the scope of the invention as dened by the claims appended hereto without departing from the invention or the principle thereof.

In the drawing:

Fig. 1 is a view partly in vertical section and partly in side elevation of a portion of a chair including the safety means of my invention;

Fig. 2 is a view in transverse section taken on the line 2 2 of Fig. 1; and

Fig. 3 is a vertical section taken on the line 3 3 of Fig. 2.

In the drawing I have shown at 1 a frag- 931. Serial N0. 527,642

mentary portion of the supporting pedestal for the chair which is provided with an opening as indicated at 2 within which is mounted a socket or bearing member 3 which is sustained in place by means of a ange 4 which rests upon the top of the part 1. A bearing sleeve 5 is mounted within the socket member 3 the lower end of which rests upon the bottom of the said socket member. A stem 10 constituting a part of a chair iron projects into the bearing member 5 and is vertically adjustable relatively to the latter by means of known construction including an adjusting screw 11. The chair iron is held with the stem 10 projecting into the sleeve 5 by means of a spring pressed catch l2 also in known manner. The stem 10 of the chair iron terminates at its upper end in a head 15 provided with an upwardly extending projection 16, the said projection being integral with or otherwise secured to the said head. An opening 17 is provided in the projection 16 as shown in Figs. 2 and 3 and the said projection also is provided at the opposite edges of its rear side with outwardly extending projections 18 having openings 19 therethrough. The front side of the projection 16 on opposite sides of the opening 17 is provided with notches 20 with which the edges of wedgeshaped projections 21 are engaged. The said projections extend outwardly from a short tubular member 22 which may project as shown part way into the opening 17. A spreader of i11- verted U shape having a top crosswise extending portion 23 and opposite sides or leg portions 24 is pivotally connected by means of a pivot rod 25 to the head 15. The pivot rod extends through openings provided in the lower ends of the opposite sides 24 of the spreader. Angle irons 26 of usual construction are secured by means of rivets to the opposite sides 24 of the spreader. The opposite ends of these angle irons extend toward the front and rear from the spreader, are curved upwardly as shown in Fig. 1 of the drawing and are connected at their opposite ends in known manner to the chair seat 27. A back partially shown at 28 may be connected in known manner to the chair seat. For the purpose of retaining the chair seat in the position in which it is shown in Fig. 1 of the drawing I have provided a tensioning bolt 30 the front end portion of which extends through the opening 17 and through the tubular member 22 and is screwthreaded for engagement with an adjusting tubular nut 31. The rear end of the tensioning bolt 30 is provided with a head 32 adjoining which is a squared portion 33 which engages a squared opening 34 provided in a cross bar 35. Coiled springs 36 are seated at their rear ends against the front sides of the opposite end portions of the cross bar and at their opposite front ends against the rear sides of the opposite end portions of a similar cross bar 37. The opposite ends of the front side of the cross bar 37 are seated against the rear edges of the sides 24 of the spreader as shown at 38. For preventing lengthwise movement of the cross bar 37 in directions transversely of the sides 24 of the spreader, I have provided ears 39 which engage the inner sides of the rear edge portions of the parts 24. For preventing descending or downward movement of the cross bar 37 I have provided midway of the center of its upper edge portion a forwardly projecting lug or ear 40 which engages the upper side of a depressed strip portion 41 of the top portion 23 of the spreader. The springs 36 are under tension and exert pressure in opposite directions to hold the cross bar 35 rmly against the front side of the head 32 of the bolt 30 and also to hold the bar 37 at all times against the rear edges of the sides 24 of the spreader.

As a safety means to prevent unrestrained backward tilting of the seat 27 and the back of the chair in case of a breakage or collapsing of the tensioning bolt 30, I have provided a U- shaped member 42 the opposite sides 43 of which extend through openings 45 through the cross bar 35 near its opposite ends, through the coiled springs 36, and also through openings through the cross bar 37 near its opposite ends. In practice the U-shaped member will be constructed of a rod of metal bent to the shape shown but may consist of a member cast or otherwise formed into proper shape.

The cross bar 47 of the U-shaped member is bent or deflected laterally so as not to interfere with the head 32 of the tensioning bolt 30. The

s front ends of the sides 43 of the U-shaped member 42 extend through the openings 19 previously referred to. Nuts 48 have adjustable screw-threaded connection with the front ends of the sides 43.

l Springs 49 are coiled about the sides 43 near their front ends, the said springs being located between the ears 18 and the nuts 48. The rear ends of the said springs are seated against the front sides of the ears 18 while the front ends thereof are seated against the rear sides of the nuts 48. By adjusting the nuts 48 the tension of the springs 49 may be varied. -The springs 49 being under tension or compression, their tendency to expand will at all times hold the rear cross portion 47 against the rear side of the cross bar 35 and will prevent lrattling thereof. Upon an adjustment of the tubular nut 31 toward the rear upon the bolt 30 the latter will be adjusted or moved toward the front to cause movement of the bar 35 toward the front to cause compression of the springs 36. Upon movement of the bar 35 toward the front the U-shaped member 42 likewise will be caused to move toward the front as a result of expansion of the springs 49. Upon adjustment of the tubular nut 31 toward the front with respect to the bolt 30 the springs 36 will expand to cause rearward movement of the cross bar 35. Rearward movement of the latter' will cause a corresponding movement of the U-shaped 4 member including the sides 43 to compress the springs 49. It will be apparent from the foregoing that the U-shaped member of the safety means is held at all times tightly against the cross bar 35 and that rattling will be entirely prevented.

Upon the tilting backward of the chair the spreader will be moved backwardly about the pivot rod 25. Such backward movement will cause similar movement of the cross bar 37 to compress the springs 36 and impose a rearwardly exerted force upon the cross bar 35 and the tensioning bolt 30. If it should happen that at such time the bolt 30 should break so as to remove the resistance offered thereby to the rearward tilting movement of the chair seat such tilting movement would be resisted by the U-shaped safety means including the opposite sides 43. Rearward movement of the U-shaped safety means would be yieldingly resisted by the coiled springs 49. Tilting movement of the chair toward the front is limited by contact of the depressed strip 4l with the rear side of the upper end of the projection l5.

It will be seen that by my invention I have provided means whereby the safety factor against accidents due to an unrestrained backward tilting of the chair seat and back is greatly increased.

Having thus described my invention what I,

claim and desire to secure by Letters Patent is:

l. In a chair, the combination of a chair iron, a

seat, means pivotally connecting said seat to the said chair iron, spring means tending to cause pivotal movement of said seat in one direction and resistng pivotal movement thereof in the opposite direction, including means for holding and tensioning the springs of said spring means, and supplemental means for holding said springs when the means for holding and tensioning the said springs becomes ineectual- 2. In a chair, the combination of a seat, a support therefor, means pivotally connecting said seat to said support, spring means tending to cause pivotal movement of said seat in one direction and resisting movement thereof in the opposite direction, including a device for holding the springs of said spring means and varying the tension thereof, and supplemental means for holding said springs, eifective upon the breaking of the device for holding said springs and varying the tension thereof.

3. In a chair, the combination of a seat, a support therefor, means pivotally connecting said seat to the said support, a pair of springs tending to cause pivotal movement of said seat in one direction and to resist the pivotal movement thereof in the opposite direction, a bolt interconnecting said springs and said support for holding and adjusting the tension of said springs, supplemental means for holding said springs when said bolt becomes ineffectual, and yielding means resisting movement of said supplemental means in one direction.

4. In a chain, the combination of a seat, a support therefor, means pivotally connecting said seat to said support, a pair of springs tending to cause pivotal movement of said seat toward the front and resisting pivotal movement thereof in the opposite direction, a cross bar against which one end of each of said springs is seated, a bolt upon which said cross bar is mounted, means for effecting adjustment of said bolt lengthwise to vary the tension of said springs, supplemental means in engagement with the said cross bar and operative, when said bolt becomes ineffectual, to resist unrestrained movement of said cross bar, and means for yieldingly holding said supplemental means in engagement with said cross bar.

5. In a chair, the combination of a seat, a support therefor having a projection extending upwardly therefrom toward the seat, means for pivotally connecting said seat to said support, a cross bar seated against said connecting means, a cross bar spaced from and in rear of the rst named cross bar, both of said cross bars having openings therethrough near their opposite ends and also through their middle portions, coiled springs interposed between the opposite end portions of said cross bars in alignment with the openings through said end portions, a bolt extending through the openings at the middle portions of said cross bars, the rear cross bar being supported by the said bolt, means for adjusting said bolt lengthwise to vary the tension of the said springs, a U-shaped member having its opposite sides extended through the openings through the opposite end portions of the said cross bars the said sides extending toward the front of the said chair, and means for yieldingly engaging the front ends of the said sides for yieldingly holding the rear end of the said U-shaped member against the rear side of the rear cross bar.

6. In a chair, the combination of a seat, a support therefor, said support having a projection from its upper end which extends toward the said seat, said projection having laterally extended ears which are provided with openings, a spreader for pivotally connecting the said seat to the said support, said spreader having spaced sides arranged in planes extending from front to rear of the said chair, a cross bar seated at its opposite ends against said sides, a second cross bar located in rear of the first named cross bar and spaced therefrom, both of said cross bars having openings through their opposite end portions, the said openings being in alignment with each other and also having openings in alignment through their middle portions, coiled springs located between the opposite end portions of the said cross bars and in alignment with the openings through said opposite end portions, a bolt for tensioning said springs, said bolt extending through the openings located in the middle portions of the said cross bars, means having connection with the front end of said bolt to effect lengthwise adjustment of the latter to vary the distance between the said cross bars to thereby vary the tension of the said springs, a U-shaped member having its opposite sides extended from the rear toward the front through the openings in the opposite end portions of the said cross bars, the front end portions of the sides of said U-shaped member extending through the openings provided in the laterally extending ears upon the opposite sides of the projection which extends upwardly from the said support, nuts having screw-threaded connection with the front ends of the sides of said U-shaped member, and yielding means located between the said ears and the said nuts, said last mentioned means being under tension.

7. In a chair, the combination of a seat, a support therefor, said support having a projection from its upper end which extends toward the said seat, said projection having laterally extended ears which are provided with openings, a spreader for pivotally connecting the said seat to the said support, said spreader having spaced sides arranged in planes extending from front to rear of the said chair, a cross bar seated at its opposite ends against said sides, a second cross bar located in rear of the rst named cross bar and spaced therefrom, both of said cross bars having openings through their opposite end portions the said openings being in alignment With each other and also having openings in alignment through their middle portions, coiled springs located between the opposite end portions of the said cross bars and in alignment with the openings through said opposite end portions, a bolt for tensioning said springs, said bolt extending through the openings located in the middle portions of the said cross bars, means having connection with the front end of said bolt to effect lengthwise adjustment of the latter to vary the distance between the said cross bars to thereby vary the tension of the said springs, a U-shaped member having its opposite sides extended from the rear toward the front through the openings in the opposite end portions of the said cross bars, the front end portions of the sides of said U-shaped member extending through the openings provided in the laterally extending ears upon the opposite sides of the projection which extends upwardly from the said support, nuts having screw-threaded connection with the front ends of the sides of said U-shaped member, and springs coiled about the opposite sides of said U-shaped member and being located between the said ears and the said nuts.

8. In a chair, the combination of a seat, a support, said support having ears connected therewith which ears extend in directions transversely of a plane from front to rear of the said chair, said ears having openings therethrough, means for pivotally connecting said seat to the said support, spring means tending to cause pivotal movement of said seat in one direction and resisting pivotal movement in the opposite direction, including a device for varying the tension of the springs of said spring means, a U-shaped member having its opposite sides extended from the rear toward the front through said springs and the openings in said ears, the said U-shaped member being pressed rearwardly by the said springs, means for retaining the said U-shaped member in engagement with the said ears, and yielding means interposed between the said ears and the said retaining means, said yielding means resisting the rearward pressure exerted upon the said U-shaped member by the said springs.

WILLIAM A. SENGPIEL. 

